1981 YT125 Stud Duck Questions

[generallee2005]

Had a little time to mess with the seals today, I pulled the old one out & found its measurements to be SW 28-40-8, the new seals size is SD 25-40-8 & is in the Yamaha bag, with the correct part number (93103-25125-00) according to http://www.cyclepartsnation.com/oemp...ton-yt125g-h-j

What is the difference between SW & SD, on the link both are part #17 & what will make a $3 difference.

I typed in the measurements off my original seal into eBay & got a search that listed many other machines, but no yt's. According to the auction, the measurements fit "FITS LEFT ON SOME AND RIGHT ON OTHERS. DT80 1983 (RIGHT SIDE), GTMXD 1977 ( RIGHT SIDE), IT175 1982-1983 (LEFT), YZ100 1977, 1982-1983, YZ125 1982-1985 (RIGHT SIDE), YZ60 1983, YZ80 1982-2001 (RIGHT SIDE).

NEW OLD STOCK OEM PART #93103-28126-00. 1- NEW LEFT SIDE CRANK SEAL. MHSD 28 X 40 X 8. "

My cylinder does say 123cc on the side, & I've checked the vin to find out the year, so what's up?

[old-yellow]

i have never ran into the problem you have, i always order my crankshaft seals from http://www.yamaha-motor.com/partview...125K_-_1983%29 or bikebandit with no problems and yes i know it says for 1983 but there the same seals used for 80-82 YT125's Yamaha just doesn't show them for 81-82 YT125's and as far as the difference between the seals if you look at this chart http://www.arai-net.com/products/product01e.pdf it will help explain the difference between SD and SW type seals, you need to use a SW type on the clutch side because there's oil and can use an SD type or SW type on the flywheel side because it don't have oil Yamaha recommends a SW type in there listing for 1983-1985 just because its a better sealing seal. I recommend you get both seals out and look at them so you know what your looking at then look them up and order them from Yamaha directly or bring them to your local Yamaha dealer and have them order them. i hope this helps

[old-yellow]

by the way the cyclenation sent you the way wrong so i would get your money back

[generallee2005]

With the Yamaha site, what I actually have is the wrong side seal. Time to reorder! Thank you for the links, I do see the difference between the seals construction now.

Here's another picture of my 250R, its actually an 81 because of the drum brake on the back, but it'll sit on ice at my grandma's barn for a while. I found out a couple of weeks ago I got into optometry school in Philly, PA! I still have more interviews to go though. The cylinder is in the bucket & the pipe is too the side, the fenders are out of picture. My wife sees junk, I see a blank canvas.

[generallee2005]

Alrighty, I got the old girl put back together finally! Everything worked great, started up on the second or third pull, idled beautifully. Then I climbed aboard & shifted into 1st gear, it lurched forward like they do when put into gear, I gave it gas and nothing but a rev, just like in neutral. Ok, a minor set back I thought, I shifted to second, same thing, a small lurch forward when it went into gear & nothing but a free revving motor. All the gears were like this, then the motor stopped & I guess it had flooded out because I couldn't get it to start again, but honestly after fiddling with it all day & no victory ride, I was somewhat disgusted. I think it may be just that I don't have the clutch set up properly, but how do I go about troubleshooting this? I know the first time I had buttoned everything up, I tightened the little bolt with the 2 lock nuts, that you see when you take the case cover off where you put the transmission oil in, & that wouldn't let me change gears, so maybe I made it too loose?

Another question, I think my needle is sticking because sometimes gas just flows out of the overflow in the back of my carb. Everything is clean as a whistle, is there anyway to stop this? Maybe buff it out with some, I dunno, 1000 grit sandpaper or something? It usually stops with a light tap on the carb to loosen everything.

[generallee2005]

Anybody have a good trick to cleaning a petcock? Mine is filthy, I've got it soaking in mineral spirits, the spirits won't hurt the rubber & should dissolve the gunk slowly. Then I think run a pipe cleaner from the kiddos arts & crafts bucket through it. I liked the little bitty filter that was on the reserve pick up, good idea 30 years ago.

I did adjust the clutch today, but the carb wasn't getting enough gas which lead to me taking the petcock apart. I should know if this works out tomorrow afternoon if all goes to plan!

[old-yellow]

i just soak mine in gas then use pipe cleaners and compressed air, it kinda sucks i just tried looking for a replacement filter but you cant get them i thought you still could.

[generallee2005]

I think I need a new carb, new carb is about the same price as a piece by piece rebuild thru bike bandit. I'm thinking going with this one http://www.bikebandit.com/mikuni-rou...retor?m=147129, I see that the 125's have a 20mm carb. Would there be any advantage to going with a bigger carb for just a machine to tootle around on & pop wheelies? On second thought, I don't think I want the headache of finding a new intake boot & boot for the air filter, but I can be persuaded.

With the carb I have now, I've taken it apart, cleaned soaked, & blew air thru it at least 5 times. Still once it cranks it idles for a bit, but once you give it a chance the motor dies & won't start back for 20 minutes at least. I've got good spark, excellent gas flow, & a brand new Uni air filter. Maybe the ethanol gas sitting in it, before I got ahold of it, ruined the carb.

[Highhorse78]

I would check and verify that your float level is set correctly. Could be starving it of fuel. Also make sure nothing is blocking the breather in the gas cap.

[old-yellow]

i just re-read the whole thread to refresh my memory and try and help more but this is what i came up with, check the float just like highhorse said to make sure its not making it run rich and staling the motor and i dont know if what am thinking is correct or not on this, but are you still missing the baffle out of the exhaust that could be messing with the back pressure in the pipe and throwing off how the exhaust scavenges the air-fuel mixture into the cylinder.

[Honda250RinNC]

i bought a brand new in box carb on ebay for $34 its the same size as a blaster carb. if u want a link let me know..it works great

[old-yellow]

and no i would not go with a bigger carb because you would have do plug chops to get the jetting right for the bigger and that can get very time consuming and start to run you up on money and when you can go with stock and save the hassle. not worth it to me anyways

[generallee2005]

I'll check the floats, on Friday morning, a little closer before ordering a new one. I know the gas tank breather is good, I've drained the tank a few times without taking the gas cap off & it drained fast & with steady flow. Where would the baffle be in the exhaust pipe? I had the pipe off while I changed the crankshaft seal, & looked at the pipe out of curiosity pretty good, but I don't remember seeing a baffle. Would I be able to see it easily? I imagine it would be close to the front of the pipe.

Again, I want to thank all of you guys that have taken the time to help me out!

On a side note, this may be a silly question (but the only silly question is one not asked) is there a difference between a 2-stroke carb & a 4 stroke carb? Thanks for the offer Honda150RinNC, but at the moment I'll pass.

[old-yellow]

the baffle is at the back end of the pipe. here's a exploded view part #19 the thing is when i got my yt125 mine was missing too, but it ran and drove just had no top end power, sometimes when i would get on it, it would fall on its face and die also so am not a hundred percent if am right on it being the baffle making it act like its is. i am a little stumped on whats going on with it so hopefully some 2-stroke gods will jump in and help

[old-yellow]

here's your pic and thats how i know your baffle was missing